Peroxisome biogenesis and selective degradation converge at Pex14p

We have analyzed the function of Hansenula polymorpha Pex14p in selective p eroxisome degradation. Previously, we showed that Pex14p was involved in pe roxisome biogenesis and functions in peroxisome matrix protein import. Evid ence for the additional function of HpPex14p in selective peroxisome degrad ation (pexophagy) came from cells defective in HpPex14p synthesis. The sugg estion that the absence of HpPex14p interfered with pexophagy was further a nalyzed by mutational analysis. These studies indicated that deletions at t he C terminus of up to 124 amino acids of HpPex14p did not affect peroxisom e degradation. Conversely, short deletions of the N terminus (31 and 64 ami no acids, respectively) of the protein fully impaired pexophagy. Peroxisome s present in these cells remained intact for at least 6 h of incubation in the presence of excess glucose, conditions that led to the rapid turnover o f the organelles in wild-type control cells. We conclude that the N terminu s of HpPex14p contains essential information to control pexophagy in H. pol ymorpha and thus, that organelle development and turnover converge at Pex14 p.